Abstract：
Fe2+ has been commonly selected to activate peroxydisulfate(PDS) for sulfate radical(SO4-·) generation because of its eco-friendly, cost-effective, and high activity characteristics. However, Fe2+ can be rapidly oxidized to Fe3+ in the reaction, leading to poor utilization of iron for PDS activation. Further, a fairly high concentration of Fe2+ is generally required and may cause iron sludge production and secondary pollution. In this study, a minute Fe2+-activated PDS system induced by bisulfite(BS) was used to degrade paracetamol(APAP) in water. The results showed that the Fe2+-PDS system could be enhanced by the circulation of Fe2+-Fe3+ with the injection of BS and by keeping Fe2+ at a high concentration. Under the optimal conditions(PDS=0.6 mol·L-1; BS=0.4 mol·L-1; Fe2+=10 μmol·L-1; pH=4), 100% APAP(4 μmol·L-1) was removed within 180 s. The degradation rate of APAP increased with the increase in BS(0-0.6 mmol·L-1) and PDS(0.2-1.5 mmol·L-1) concentration, and a modest Fe2+ concentration could accelerate APAP removal. Co-existing substances inhibited the APAP removal and followed the order of HCO3->HPO42->Cl->NO3->humic acid(HA). Based on the quenching experiments and electron paramagnetic resonance spectroscopy test, SO4-· was shown to be the primary reactive species for APAP decomposition in the BS-Fe2+-PDS process. Three-dimensional fluorescence spectroscopy revealed that APAP intermediates had fluorescence characteristics. Moreover, five intermediates were identified, and the probable APAP degradation pathways were proposed. The removal efficiencies of APAP were lower in real waters than that in ultrapure water. Nevertheless, the removal effect was greatly improved after a prolonged reaction time. All results indicated that the BS-Fe2+-PDS system could be a promising method for organic pollutant treatment.
摘要：
由于Fe2环保，通常被选择用于激活过氧二硫酸盐（PDS）以生成硫酸盐自由基（SO4-·），成本效益高,和高活性特性。然而,Fe2+可以在反应中迅速氧化为Fe3+,导致铁用于PDS活化的利用率低。Further,通常需要相当高浓度的Fe2+，可能会导致铁污泥的产生和二次污染。在这项研究中,使用亚硫酸氢盐（BS）诱导的微小Fe2激活的PDS系统降解水中的对乙酰氨基酚（APAP）。结果表明，通过注入BS循环Fe2-Fe3并保持高浓度的Fe2可以增强Fe2-PDS系统。在最佳条件下（PDS=0.6mol·L-1；BS=0.4mol·L-1；Fe2=10μmol·L-1；pH=4），在180s内去除100％的APAP（4μmol·L-1）。随着BS（0-0.6mmol·L-1）和PDS（0.2-1.5mmol·L-1）浓度的增加，APAP的降解速率增加。适度的Fe2+浓度可以加速APAP的去除。共存物质抑制了APAP的去除，并遵循HCO3->HPO42->Cl->NO3->腐殖酸（HA）的顺序。基于猝灭实验和电子顺磁共振光谱测试,SO4-·被证明是BS-Fe2-PDS过程中APAP分解的主要反应性物质。三维荧光光谱显示APAP中间体具有荧光特性。此外，确定了五个中间体，并提出了可能的APAP降解途径。在实际水中，APAP的去除效率低于超纯水。然而，延长反应时间后，去除效果大大提高。所有结果表明，BS-Fe2-PDS系统可能是一种有前途的有机污染物处理方法。
